Different Flour Microbial Communities Drive to Sourdoughs Characterized by Diverse Bacterial Strains and Free Amino Acid Profiles

This work aimed to investigate whether different microbial assemblies in flour may influence the microbiological and biochemical characteristics of traditional sourdough. To reach this purpose, members of lactic acid bacteria, enterobacteria, and yeasts were isolated from durum wheat flour. Secondly, the isolated microorganisms (Pediococcus pentosaceus, Saccharomyces cerevisiae, Pantoea agglomerans, and Escherichia hermannii) were inoculated in doughs prepared with irradiated flour (gamma rays at 10 kGy), so that eight different microbial assemblies were obtained. Two non-inoculated controls were prepared, one of which (C-IF) using irradiated flour and the other (C) using non-irradiated flour. As shown by plate counts, irradiation of flour caused total inactivation of yeasts and a decrease of all the other microbial populations. However, acidification occurred also in the dough C-IF, due to metabolic activity of P. pentosaceus that had survived irradiation. After six fermentations, P. pentosaceus was the dominant lactic acid bacterium species in all the sourdoughs produced with irradiated flour (IF). Yet, IF-based sourdoughs broadly differed from each other in terms of strains of P. pentosaceus, probably due to the different microorganisms initially inoculated. Quantitative and qualitative differences of free amino acids concentration were found among the sourdoughs, possibly because of different microbial communities. In addition, as shown by culture-independent analysis (16S metagenetics), irradiation of flour lowered and modified microbial diversity of sourdough ecosystem

Technological, functional and safety aspects of enterococci in fermented vegetable products: a mini-review

Bacteria belonging to the genus Enterococcus spp.—a member of the lactic acid bacteria group—are natural inhabitants of various environments, including vegetable products. Although some strains show pathogenic determinants, overall these bacteria may have some pro-technological features. Some enterococci have been described as potential starter or protective cultures in the dairy industry, since they contribute to the organoleptic and quality characteristics of dairy products. Although several fermented vegetable products have a long history in human nutrition, studies regarding autochthonous enterococci and their application to fermented vegetable foods are much less numerous than those concerning dairy foods. In this review, after a general overview of enterococci, their presence and role in fermented vegetable foods (including table olives, sauerkraut, kimchi, tomato juice, French beans, caper berries and cereal-based products) will be covered

Protein sources alternative to meat: state of the art and involvement of fermentation

Meat represents an important protein source, even in developing countries, but its production is scarcely sustainable, and its excessive consumption poses health issues. An increasing number of Western consumers would replace, at least partially, meat with alternative protein sources. This review aims at: (i) depicting nutritional, functional, sensory traits, and critical issues of single-cell proteins (SCP), filamentous fungi, microalgae, vegetables (alone or mixed with milk), and insects and (ii) displaying how fermentation could improve their quality, to facilitate their use as food items/ingredients/supplements. Production of SCP (yeasts, filamentous fungi, microalgae) does not need arable land and potable water and can run continuously, also using wastes and byproducts. Some filamentous fungi are also consumed as edible mushrooms, and others are involved in the fermentation of traditional vegetable-based foods. Cereals, pseudocereals, and legumes may be combined to offer an almost complete amino acid profile. Fermentation of such vegetables, even in combination with milk-based products (e.g., tarhana), could increase nutrient concentrations, including essential amino acids, and improve sensory traits. Different insects could be used, as such or, to increase their acceptability, as ingredient of foods (e.g., pasta). However, insects as a protein source face with safety concerns, cultural constraints, and a lack of international regulatory framework.info:eu-repo/semantics/publishedVersio

Massive non-natural proteins structure prediction using grid technologies

Background The number of natural proteins represents a small fraction of all the possible protein sequences and there is an enormous number of pr oteins never sampled by nature, the so called "never born proteins" (NBPs). A fundamental question in this regard is if the ensemble of natural proteins possesses peculiar chemical and physical properties or if it is just the product of contingency coupled to functional selection. A key feature of natural proteins is thei r ability to form a well defined three-dimensional structure. T hus, the structural study of NBPs can help to understand if natural protein sequences were selecte d for their peculiar properties or if they are just one of the possible stable and functional ensembles. Methods The structural characterization of a huge number of random proteins cannot be approached experimentally, thus the problem has been tackled using a computational approach. A large random protein sequences library (2 × 10 ^4 sequences) was generated, discarding amino acid sequences with significant simi larity to natural proteins, and the corresponding structures were predicted using Rosetta. Given th e highly computational demanding problem, Rosetta was ported in grid and a user friendly job submission environment was developed within the GENIUS Grid Portal. Protein structures generated were analysed in terms of net charge, secondary structure content, surface/volume ratio, hydrophobic core composition, etc. Results The vast majority of NBPs, according to the Rosetta mode l, are characterized by a compact three-dimensional structure with a high secondary structure content. Structure compactness and surface polarity are comparable to those of natural proteins, suggesting similar stability and solubility. Deviations are observed in α helix- β strands relative content and inydrophobic core composition, as NBPs appear to be richer in helical structure and aromatic amino acids with respect to natural proteins. Conclusion The results obtained suggest that the abil ity to form a compact, ordered and water-soluble structure is an intrinsic property of polypeptides. The tendency of random sequences to adopt α helical folds indicate that all-α proteins may have emerged ea rly in pre-biotic evolution. Further, the lower percentage of aromatic residu es observed in natural proteins has important evolutionary implications as far as tolerance to mutati ons is concerned

Manufacture of a functional fermented milk enriched of Angiotensin-I Converting Enzyme (ACE)-inhibitory peptides and γ-amino butyric acid (GABA)

Abstract This study aimed at developing and characterizing a fermented milk with a potentially anti-hypertensive effect due to the concurrent presence of Angiotensin-I Converting Enzyme (ACE)-inhibitory peptides and γ-amino butyric acid (GABA). Preliminarily, lactic acid bacteria strains were screened based on the capacity of releasing ACE-inhibitory peptides and of synthesizing GABA. The most potent RP-FPLC fraction from the milk fermented with Lactococcus lactis DIBCA2 had an ACE-inhibitory activity, expressed in terms of IC 50 , of 5 ± 2 μg/mL, a value which compares well to those reported for the majority of ACE-inhibitory peptides identified in fermented milks. This fraction contained a mixture of six peptides, five of which shared motifs in common with ACE-inhibitory peptides previously reported. Lactobacillus plantarum PU11 was selected as the highest producer of GABA, ca. 77.4 mg/kg after 120 h of milk fermentation. Both the strains were selected and used as starters for consecutive milk fermentation. After fermentation, the milk contained both the lactic acid bacteria at the cell density of ca. 8.0 log CFU/mL, had a pH of ca. 4.45, and showed ACE-inhibitory activity (IC 50 = 0.70 ± 0.07 mg/mL) and a concentration of GABA (ca. 144.5 mg/kg), which were compatible with the dosage for mild antihypertensive effect

Sustainable and Health-Protecting Food Ingredients from Bioprocessed Food by-Products and Wastes

Dietary inadequacy and nutrition-related non-communicable diseases (N-NCDs) represent two main issues for the whole society, urgently requesting solutions from researchers, policy-makers, and other stakeholders involved in the health and food system. Food by-products and wastes (FBPW) represent a global problem of increasing severity, widely recognized as an important unsustainability hotspot, with high socio-economic and environmental costs. Yet, recycling and up-cycling of FBPW to produce functional foods could represent a solution to dietary inadequacy and risk of N-NCDs onset. Bioprocessing of FBPW with selected microorganisms appears to be a relatively cheap strategy to yield molecules (or rather molecules mixtures) that may be used to fortify/enrich food, as well as to formulate dietary supplements. This review, conjugating human health and sustainability in relation to food, describes the state-of-the-art of the use of yeasts, molds, and lactic acid bacteria for producing value-added compounds from FBPW. Challenges related to FBPW bioprocessing prior to their use in food regard will be also discussed: (i) loss of product functionality upon scale-up of recovery process; (ii) finding logistic solutions to the intrinsic perishability of the majority of FBPW; (iii) inserting up-cycling of FBPW in an appropriate legislative framework; (iv) increasing consumer acceptability of food and dietary supplements derived from FBPWThis research was funded by the project SYSTEMIC “an integrated approach to the challenge of sustainable food systems: adaptive and mitigatory strategies to address climate change and malnutrition”, Knowledge hub on Nutrition and Food Security, that has received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS and FACCE-JPI launched in 2019 under the ERA-NET ERAHDHL (n° 696295). Francisca Rodrigues (CEECIND/01886/2020) is thankful for her contract financed by FCT/MCTES—CEEC Individual 2020 Program Contractinfo:eu-repo/semantics/publishedVersio

Enhancing nutritional and sensory properties of plant-based beverages: a study on chickpea and Kamut® flours fermentation using Lactococcus lactis

The study aimed to set up a protocol for the production of a clean-label plant-based beverage (PBB), obtained by mixing chickpeas and Kamut® flours and using a commercial Lactococcus lactis (LL) as fermentation starter, and to characterize it, from nutritional, microbiological, textural, shelf-life, and sensory points of view. The effect of using the starter was evaluated comparing the LL-PBB with a spontaneously fermented beverage (CTRL-PBB). Both PBBs were high in proteins (3.89/100 g) and could be considered as sources of fiber (2.06/100 g). Notably, L. lactis fermentation enhanced the phosphorus (478 vs. 331 mg/kg) and calcium (165 vs. 117 mg/kg) concentrations while lowering the raffinose content (5.51 vs. 5.08 g/100 g) compared to spontaneous fermentation. Cell density of lactic acid bacteria increased by ca. two log cycle during fermentation of LL-PBB, whereas undesirable microbial groups were not detected. Furthermore, L. lactis significantly improved the beverage’s viscosity (0.473 vs. 0.231 Pa s), at least for 10 days, and lightness. To assess market potential, we conducted a consumer test, presenting the LL-PBB in “plain” and “sweet” (chocolate paste-added) variants. The “sweet” LL-PBB demonstrated a higher acceptability score than its “plain” counterpart, with 88 and 78% of participants expressing acceptability and a strong purchase intent, respectively. This positive consumer response positions the sweet LL-PBB as a valuable, appealing alternative to traditional flavored yogurts, highlighting its potential in the growing plant-based food market

On Predicting Recurrence in Early Stage Non-small Cell Lung Cancer

Early detection and mitigation of disease recurrence in non-small cell lung cancer (NSCLC) patients is a nontrivial problem that is typically addressed either by rather generic follow-up screening guidelines, self-reporting, simple nomograms, or by models that predict relapse risk in individual patients using statistical analysis of retrospective data. We posit that machine learning models trained on patient data can provide an alternative approach that allows for more efficient development of many complementary models at once, superior accuracy, less dependency on the data collection protocols and increased support for explainability of the predictions. In this preliminary study, we describe an experimental suite of various machine learning models applied on a patient cohort of 2442 early stage NSCLC patients. We discuss the promising results achieved, as well as the lessons we learned while developing this baseline for further, more advanced studies in this area

Never born proteins as a test case for ab initio protein structures prediction

The number of natural proteins although large is significantly smaller than the theoretical number of proteins that can be obtained combining the 20 natural amino acids, the so-called “never born proteins” (NBPs). The study of the structure and properties of these proteins allows to investigate the sources of the natural proteins being of unique characteristics or special properties. However the structural study of NPBs can also been intended as an ideal test for evaluating the efficiency of software packages for the ab initio protein structure prediction. In this research, 10.000 three-dimensional structures of proteins of completely random sequence generated according to ROSETTA and FOD model were compared. The results show the limits of these software packages, but at the same time indicate that in many cases there is a significant agreement between the prediction obtained